Inhibition of cloned human L-type cardiac calcium channels by 2,3-butanedione monoxime does not require PKA-Dependent phosphorylation sites

Jörg Eisfeld, G. Mikala, Gyula Varadi, Arnold Schwartz, Udo Klöckner

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The oxime derivative 2,3-butanedione monoxime (BDM) is used as an inorganic phosphatase to probe the phosphorylation state of many cellular proteins including the L-type calcium channel in various tissues. We used BDM further to shed light on the controversy surrounding direct phosphorylation of the L-type Ca2+ channel. We employed a recombinant system that utilizes HEK 293 cells expressing wild type and mutant human heart calcium channels. BDM reversibly reduced the calcium channel current induced by expression of the wild type channel in a concentration-dependent manner with an apparent IC50 value of 15.3 mM. Deletion of part of the carboxyl terminus of the α1 subunit, which contains one putative protein kinase A site, or mutating all of the protein kinase A consensus sites of the pore forming subunit, did not significantly change the apparent IC50 value or alter in any other way the blocking effect of BDM on the expressed currents. Our data suggest that BDM produces reversible modifications of the cardiac calcium channel protein leading to an expected reduction in the amplitude of the expressed currents, but the site of action must be different from that of the consensus sites for protein kinase A dependent phosphorylation.

Original languageEnglish
Pages (from-to)489-492
Number of pages4
JournalBiochemical and Biophysical Research Communications
Volume230
Issue number3
DOIs
Publication statusPublished - Jan 23 1997

Fingerprint

L-Type Calcium Channels
Phosphorylation
Calcium Channels
Cyclic AMP-Dependent Protein Kinases
Inhibitory Concentration 50
Oximes
HEK293 Cells
Induced currents
Phosphoric Monoester Hydrolases
Proteins
Cells
diacetylmonoxime
Tissue
Derivatives

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

Cite this

Inhibition of cloned human L-type cardiac calcium channels by 2,3-butanedione monoxime does not require PKA-Dependent phosphorylation sites. / Eisfeld, Jörg; Mikala, G.; Varadi, Gyula; Schwartz, Arnold; Klöckner, Udo.

In: Biochemical and Biophysical Research Communications, Vol. 230, No. 3, 23.01.1997, p. 489-492.

Research output: Contribution to journalArticle

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